Projection screen having elongated structures

ABSTRACT

A light managing screen may provide a rear projection screen, front projection screen or component thereof. The screen may comprise a polymeric composition including a first polymeric material, and a second polymeric material disposed as a plurality of elongated structures within the first polymeric material. Each elongated structure has a major axis and the major axes are substantially aligned. The first polymeric material has an index of refraction that differs by at least 0.01 from an index of refraction of the second polymeric material. In some instances, a pressure sensitive adhesive material is selected as the first polymeric material. The orientation of the elongated structures and the difference in indices of refraction results in the polymeric composition scattering light asymmetrically.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. Ser. No. 09/761896, filedJan. 17, 2001, now allowed, the disclosure of which is hereinincorporated by reference.

FIELD

This invention relates to projection screens having an elongateddispersed phase polymeric material disposed in another polymericmaterial.

BACKGROUND

Optical films and other devices have been developed for a variety ofapplications, including for use as decorative articles and to enhance oralter characteristics of displays. In particular, there are instanceswhen it is desirable to anisotropically reflect or otherwise scatterlight. For example, in many display and projection screen applications,a broad horizontal viewing angle is desirable because a user or viewermay be positioned to the side of the display or projection screen. Onthe other hand, the vertical viewing angle typically does not need to beas broad because the user or viewer is typically positioned with thedisplay or projection screen at or near eye level. Accordingly, it canbe desirable to have an anisotropic display with a relatively broadhorizontal viewing angle, but a relatively narrow vertical viewingangle.

One method to modify the viewing angle includes the use of surfacestructure, such as a lenticular lens screen, where one dimensional lensstructures are molded onto plastic substrates. Light is focused by thecylindrical-like lens structures onto a diffusive film to achieveasymmetric diffusion. However, lenticular screens contain a series oftangible grooves which can be expressed as a frequency. This frequencycan interfere with the pixel frequency in liquid crystal basedprojection displays and generate Moire fringes. Thus, the use of currentlenticular screens is limited for high definition image display in whichpixel frequencies are higher.

SUMMARY OF THE INVENTION

Generally, the present invention relates to screens for managing lightsuch as a rear projection screen or a front projection screen. Thepresent invention may be useful as the screen itself or as a componentof such as screen. Optical systems incorporating such screens orcomponents are also included in the ambit of the present invention. Thepresent invention utilizes polymeric compositions that can be used toanisotropically scatter light or otherwise manage light. One embodimentis a polymeric composition that includes a first polymeric material, anda second polymeric material disposed as a plurality of elongatedstructures within the first polymeric material. Each elongated structurehas a major axis and the major axes are substantially aligned. The firstpolymeric material has an index of refraction that differs by at least0.01 from an index of refraction of the second polymeric material. Insome instances, a pressure sensitive adhesive material is selected asthe first polymeric material. The orientation of the elongatedstructures and the difference in indices of refraction results in thepolymeric composition scattering light asymmetrically.

Yet another embodiment of the invention is a method of making an opticalelement such as a screen or display. A polymeric composition is formedusing a first polymeric material and a second polymeric materialdispersed in the first polymeric material. An index of refraction of thefirst polymeric material differs by at least 0.01 from an index ofrefraction of the second polymeric material. The polymeric compositionis then dispensed on a substrate. This dispensing results in the secondpolymeric material forming multiple elongated structures within thefirst polymeric. Each of the elongated structures has a major axis andthe major axes of the elongated structures are substantially aligned.

The above summary of the present invention is not intended to describeeach disclosed embodiment or every implementation of the presentinvention. The Figures and the detailed description which follow moreparticularly exemplify these embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention may be more completely understood in consideration of thefollowing detailed description of various embodiments of the inventionin connection with the accompanying drawings, in which:

FIG. 1 is a schematic top cross-sectional view of a film, according tothe invention;

FIG. 2 is a schematic side view of the film of FIG. 1 disposed on alight-guiding structure, according to the invention;

FIG. 3 is a schematic cross-sectional view of the film of FIG. 1 on afilm or device that otherwise conducts or contains light by totalinternal reflection, according to the invention;

FIGS. 4 and 5 are schematic cross-sectional views at right angles toeach other illustrating a portion of the film of FIG. 1 to demonstratescattering of light by a dispersed phase fiber in a polymeric matrix;

FIG. 6 is a graph of relative intensity (y axis) versus wavelength(x-axis) (nm) for three films (top three lines) according to theinvention, as well as a film with adhesive material and no dispersedphase material (bottom line) and a film with no adhesive material(second to bottom);

FIG. 7 is a graph of extinction ratio (y axis) versus diffusion angle (xaxis) for a film, according to the invention;

FIG. 8 is a graph of gain (y axis) versus horizontal viewing angle(solid line) and vertical viewing angle (dotted line) for one embodimentof a film, according to the invention;

FIG. 9 is a graph of gain (y axis) versus horizontal viewing angle(solid line) and vertical viewing angle (dotted line) for a secondembodiment of a film, according to the invention;

FIG. 10 is a graph of gain (y axis) versus horizontal viewing angle(solid line) and vertical viewing angle (dotted line) for a thirdembodiment of a film, according to the invention;

FIG. 11 is a schematic view of an optical system with a front projectionscreen according to an aspect of the present invention;

FIG. 12 is a sectional view of one embodiment of front projection screenaccording to the present invention;

FIG. 13 is a sectional view of another embodiment of front projectionscreen according to the present invention;

FIG. 14 is a schematic view of a rear projection system with a rearprojection screen according to another aspect of the present invention;

FIG. 15 is sectional view of one embodiment of rear projection screenaccording to the present invention;

FIG. 16 is sectional view of another embodiment of rear projectionscreen according to the present invention; and

FIG. 17 is sectional view of another embodiment of rear projectionscreen according to the present invention.

While the invention is amenable to various modifications and alternativeforms, specifics thereof have been shown by way of example in thedrawings and will be described in detail. It should be understood,however, that the intention is not to limit the invention to theparticular embodiments described. On the contrary, the intention is tocover all modifications, equivalents, and alternatives falling withinthe spirit and scope of the invention.

DETAILED DESCRIPTION

The present invention utilizes polymeric compositions having anelongated dispersed phase polymeric material disposed in anotherpolymeric material and optical elements such as screens or displays thatcontain the compositions as at least an element thereof. The presentinvention also includes methods of making the optical elements orcomponents thereof. In particular, the present invention preferablyutilizes adhesive compositions having an elongated dispersed phasematerial disposed in an adhesive material and articles containing thecompositions and methods of making and using the compositions. While thepresent invention is not so limited, an appreciation of various aspectsof the invention will be gained through a discussion of the examplesprovided below.

The following terms are defined as follows, unless otherwise stated:

“Stretch removable” means that a pressure sensitive adhesive, whenpulled and elongated (preferably from a substrate surface at a rate of30 centimeters/minute and at an angle of no greater than 45°), detachesfrom a substrate surface without significant damage to the substratesurface (e.g. tearing), and without leaving a significant residue,preferably that which is visible to the unaided human eye on thesubstrate.

“Substantially continuous” means that for an at least 0.5 centimeterlength sample of the adhesive composition taken in the machinedirection, at least 50% of the fibers present in the sample arecontinuous (i.e. unbroken).

“Tensile strength” means the maximum tensile strength at break whentested according to ASTM D 882-97, incorporated herein by reference.

The polymeric compositions utilized in the invention include at leasttwo polymeric materials, where one polymeric material is dispersed asmultiple elongated structures within the other polymeric material. Oneparticularly useful example of such a polymeric composition is anadhesive composition that includes an adhesive material and a dispersedphase material that is disposed as elongated structures within theadhesive material. The adhesive material may replaceable, permanent orrepositionable. These elongated structures of the dispersed phasematerial have a major axis, corresponding to the longest lengthdimension of the structures. The major axes of the elongated structuresare substantially aligned, at least within domains, in the polymericcomposition. The adhesive material has at least one index of refractionthat differs from an index of refraction of the dispersed phase materialby at least 0.01. In some embodiments, the polymeric composition is apressure sensitive adhesive composition that includes a pressuresensitive adhesive material as the adhesive material. The inventions arediscussed herein with respect to a polymeric composition that includesan adhesive material to illustrate the inventions and designconsiderations; however, it will be understood that the inventions canalso be applied to other non-adhesive polymeric compositions thatcontain a polymeric material dispersed as substantially aligned,elongated structures within another polymeric material. However, anon-adhesive polymeric composition lacks the potential to be laminatedto another substrate without the addition of another adhesive.

The difference in the indices of diffraction between the adhesivematerial and the dispersed phase material and the orientation of theelongated structures provides useful optical properties to the polymericcomposition. Specifically, the size, shape and position of the elongatedstructures may be altered in order to provide an optical element withpredetermined optical properties. For example, the polymeric compositioncan anisotropically scatter light. This light can be transmitted throughor reflected by the polymeric composition. The largest scattering anglesoccur in directions substantially perpendicular to the major axes of theelongated structures. The smallest scattering angles occur in directionssubstantially parallel to the major axes of the elongated structures.For example, in a polymeric composition having the major axes of theelongated structures oriented in the vertical direction, the largestscattering angles will be observed in the horizontal direction and thesmallest scattering angles will be observed in the vertical direction.Thus, a film utilizing this polymeric composition and placed over alight source can have a substantially increased horizontal viewing angledue to the increased scattering angles as a result of the orientedelongated structures with little or no increase in the vertical viewingangle. This configuration can be particularly useful with displays andprojections screens.

In addition to optical properties, the dispersed phase material can, ifdesired, enhance or alter mechanical properties of the adhesivematerial. In particular, the dispersed phase polymeric material can act,if desired and selected to do so, to reinforce the polymeric composition(e.g., a pressure sensitive adhesive composition). The reinforcedcomposition of the present invention can have improved cohesivestrength, as represented by a higher tensile strength of thecomposition, with respect to a similar composition without the dispersedphase material. Additional description of these mechanical propertiesand examples illustrating these properties are provided in U.S. patentapplication Ser. No. 09/764478, entitled “Pressure Sensitive AdhesivesWith A Fibrous Reinforcing Material”, filed on even date herewith,Docket No. 55694US002, incorporated herein by reference, and U.S. patentapplication Ser. No. 09/764540, entitled “Stretch Removable AdhesiveArticles and Methods”, filed on even date herewith, Docket No.55959US002, incorporated herein by reference.

Typically, the elongated structures of the dispersed phase material aregenerated by mixing the adhesive material and dispersed phase materialand then applying a shear force to elongate the dispersed phasematerial. The application of a shear force in a desired directioncreates and orients the elongated structures of the dispersed phasematerial. One suitable method for applying the shear force includesdispensing the combined adhesive and dispersed phase material onto asubstrate where the dispensing includes the application of a shearforce, such as, for example, by known extrusion and coating techniques.Generally, although not necessarily, the application of a shear force isperformed at elevated temperatures and then the polymeric composition iscooled to room temperature (or a use or storage temperature) to set theshape and size of the elongated structures.

FIG. 1 illustrates a top view of one embodiment of a layer 100 of apolymeric composition, according to the invention. The layer 100includes a substantially continuous phase 102 of the adhesive materialand elongated structures 104 of the dispersed phase material. Lightincident on the polymeric composition, whether from behind astransmitted light or from above as reflected light, will be scatteredpreferentially in directions perpendicular to the major axes of theelongated structures 104, as represented by the long arrows 106. Incontrast, much less scattering will occur in directions parallel to themajor axes of the elongated structures, as represented by the shorterarrows 108.

Adhesive Material

The adhesive material can be a single adhesive or a combination of twoor more adhesives. A variety of different adhesives can be used in thepolymeric compositions of the invention. Typically, although notnecessarily, the adhesive material forms a substantially continuousmatrix within which the elongated structures of the dispersed phasematerial are disposed. In general, the selection of adhesive materialand dispersed phase material can be made based on the desired opticaland mechanical properties and the compatibility of the two (or more)materials. In particular, pressure sensitive adhesives can form usefulpolymeric compositions. Moreover, as indicated above, polymericcompositions can also be formed without adhesive materials. Generally,any polymer can be used as long as a suitable and compatible dispersedphase material can also be selected to provide the desired optical andmechanical properties.

As an example, suitable pressure sensitive adhesive materials includepressure sensitive adhesives based on natural rubbers, syntheticrubbers, styrene block copolymers, polyvinyl ethers, acrylates,methacrylates, polyolefins, and silicones. Suitable non-PSA materialsinclude any thermoplastic polymers that have a refractive indexdiffering by at least 0.03 from a refractive index of the dispersedphase material. Suitable polymers include, for example, polyacrylates,polymethacrylates, polyolefins (e.g., linear low density polyethylene,ultra low density polyethylene, and polypropylene) poly(vinyl butyral),polycarbonates, polyesters, polyethers, and polyamides.

For example, the pressure sensitive adhesive can be an acrylic pressuresensitive adhesive. Acrylic pressure-sensitive adhesives can include analkyl ester component such as, for example, isooctyl acrylate, isononylacrylate, 2-methyl-butyl acrylate, 2-ethyl-hexyl acrylate and n-butylacrylate and, optionally, a co-monomer component such as, for example,acrylic acid, methacrylic acid, vinyl acetate, N-vinyl pyrrolidone,(meth)acrylate, (meth)acrylamide, vinyl ester, fumarates and styrenemacromer. As an example, the acrylic pressure sensitive adhesive caninclude from 0 to 20 weight percent of acrylic acid or methacryclic acidand from 80 to 100 weight percent of isooctyl acrylate, 2-ethyl-hexylacrylate or n-butyl acrylate composition. One adhesive material of thepresent invention includes 2%-15% acrylic acid or methacrylic acid and85%-98% isooctyl acrylate, 2-ethyl-hexyl acrylate or n-butyl acrylate.Another adhesive material includes 2%-10% acrylic acid, 2%-10% styrenemacromer, and 85%-96% isooctyl acrylate.

The pressure sensitive adhesive can be self tacky, or tackifiers can beadded to form the pressure sensitive adhesive. Suitable tackifiersinclude, for example, rosin ester resins, aromatic hydrocarbon resins,aliphatic hydrocarbon resins, and terpene resins.

Dispersed Phase Material

The dispersed phase material can be a single compound or a combinationof two or more compounds. When multiple compounds are used, thecompounds can be miscible or immiscible with each other. When immiscibledispersed phase compounds are used, more than one type of dispersedphase will typically be present in the polymeric composition.

Various dispersed phase materials can be used. Typically, the dispersedphase material is a polymeric material. In at least some embodiments,the dispersed phase material is elastomeric and can be asemi-crystalline polymeric material. A semi-crystalline polymer cansimultaneously have both amorphous and crystalline domains. Examples ofsuitable semi-crystalline polymers include polycaprolactone (PCL),isotactic polybutene (PB), polyvinylidene fluoride, ultra low densitypolyethylene (ULDPE), linear low density polyethylene (LLDPE),metallocene polyolefins such as poly(ethylene-co-butene, hexene oroctene), and other ethylene copolymers such as ethylene-butene-hexeneterpolymers. Other suitable polymers include, for example,poly(methylmethacrylate) (PMMA), acrylics, polycarbonate, polyurethanes,and polyvinyl butyral.

The dispersed phase material is typically compatible with and immisciblewith or only slightly soluble in the adhesive material at the processingand use temperatures. The immiscibility and compatability duringcombination of the dispersed phase material and adhesive materialtypically allows a substantially uniform dispersion of the dispersedphase material within the adhesive material, if desired.

The adhesive and dispersed phase materials, as well as the amounts ofeach material and the processing conditions, are typically selected toobtain a desired dispersed phase morphology. A variety of differentshapes of the elongated structures of the dispersed phase material canbe formed. Such shapes include, for example, fibers, filaments, rods,ellipsoids, sheets, and ribbons. Moreover, these shapes can havestraight, zig-zag, sinusoidal, or other configurations. In addition, thecross-sectional shape of the elongated structures can be, for example,circular, oval, rectangular, square, triangular, or irregular.

A variety of factors can contribute to determining the dispersed phasemorphology including, for example, the shear viscosity ratio between thedispersed phase material and the adhesive material, the interfacialtension between the two materials, the shear rate, and the draw ratio.

The shear viscosities at the processing temperature at which the shearforce is applied will affect the size and shape of the structures formedby the dispersed phase material. The ratio of shear viscosities of thedispersed phase material and the adhesive material is typically in therange of 0.1 to 10. When the ratio of the shear viscosities of thedispersed phase material and the adhesive material, at the temperatureat which a shear force is applied, is near one (e.g., about 0.5 to 2),thin filaments or fibers can be formed from the dispersed phasematerial. For lower shear viscosity ratios (e.g., 0.5 or lower), sheetsor ribbons are typically formed from the dispersed phase material. Forhigher shear viscosity ratios (e.g., 2 or higher), short rods orellipsoids can be formed; although at very high shear viscosity ratios,there is typically little or no elongation of the dispersed phase (e.g.,the dispersed phase will remain spheroidal). Shear viscosity can bemeasured using, for example, a capillary rheometer, such as the InstronCapillary Rheometer available from Instron Corporation, Canton, Mass.

Interfacial tension can also be a factor in dispersed phase morphology.Low interfacial tension is generally desirable. If the interfacialtension is too large or the melt strength is too low, fibers orfilaments of the dispersed phase material can break apart during theshear flow and cooling processes. If, however, the interfacial tensionis too low, droplets of the dispersed phase material within the adhesivematerial can be difficult to coalesce with other droplets of dispersedphase material during shear flow. This can hinder the ability to obtaina long fiber or filament.

The shear rate and draw ratio will also impact the morphology of thedispersed phase. Generally, a higher shear rate will result in longerelongated structures. However, if the shear rate is too high, theelongated structures can break during shear. The shear rate at which theelongated structures break will depend on the thickness of thestructures and the other parameters described above. In addition, alarger draw ratio will generally result in longer elongated structures.

The dispersed phase material typically has a melting temperature abovethe use temperature of the polymeric composition. Similarly, thedispersed phase material typically has a melting temperature above thestorage temperature of the polymeric composition or any articlemanufactured with the polymeric composition. Preferably, the dispersedphase material has a melting temperature of at least 70° C. Meltingtemperatures can be measured by, for example, differential scanningcalorimetry (“DSC”).

In some embodiments, the dispersed phase material exists assubstantially continuous fibers. In one embodiment, the fibers are, onaverage, at least about 0.5 centimeters long and can be, on average,about 2 to about 5 cm long or more.

If diffuse light scattering is desired, the cross-sectional dimension(e.g., diameter) of the elongated structures of the dispersed phasetypically is preferably no more than several times the wavelength oflight to be scattered. Otherwise, specular light scattering willdominate. However, if the diameter of the dispersed phase is too small(e.g., about {fraction (1/30)} of the wavelength of the light to bescattered), little scattering will occur. Typically, efficient lightscattering occurs for light having wavelengths that are the same as orless than the cross-sectional dimension of the elongated structures(e.g., half the cross-sectional dimension or less). In some embodiments,fibers of dispersed phase material can be formed that have across-sectional dimension of about 0.05 to about 5 micrometers,preferably about 0.1 to about 3 micrometers. Such fibers areparticularly useful for efficient light scattering of visible light(about 380 to 750 nm).

During mixing and prior to application of the shear force, the dispersedphase material can be in the form of, for example, substantiallyspherical particles having an average particle size no more than about20 micrometers and typically no more than about 10 micrometers. Thedispersed phase material can also be provided to the mixture in otherforms.

Generally, the dispersed phase material is about 2% to about 70% byweight of the polymeric composition. Typically, the dispersed phasematerial is about 5% to about 50% by weight of the polymericcomposition. In many instances, a greater amount of dispersed phasematerial will result in more light scattering. For most loadings (unlessthe polymeric composition is very thin), scattered light typicallyundergoes several scattering events. A larger loading will typicallyincrease the percentage of light that undergoes multiple scatteringevents through the polymeric composition and also increase the averagenumber of events per photon of light.

Other materials, as described below, can also be included within thepolymeric composition depending on the desired properties of thepolymeric composition. Generally, the adhesive material is about 30% toabout 98% by weight of the polymeric composition. Typically, theadhesive material is about 50% to about 95% by weight of the polymericcomposition.

Other Materials

Other materials can be added, if desired, to modify optical or physicalproperties of the polymeric composition, including, for example, oils,plasticizers, antioxidants, antiozonants, UV stabilizers, hydrogenatedbutyl rubber, pigments, dyes, and curing agents. For example, pigmentsor dyes can be added to the polymeric composition to alter the color ofthe composition. In some embodiments, the pigment or dye provides acolor to the composition. In other embodiments, the pigment or dye isused to reduce or eliminate color from the composition. Such color canarise due to the wavelength dependency of the indices of refraction ofthe adhesive and dispersed phase materials.

In addition, an additional diffuse or specular scattering material canbe included in the polymer composition, if desired. This scatteringmaterial has at least one index of refraction different than an index ofrefraction of the adhesive material. This additional scattering materialis not substantially oriented within the adhesive material. For example,the scattering material is substantially spherical or is randomlyoriented within the adhesive material.

Mixing

The dispersed phase material is mixed with the adhesive material beforesubjecting the mixed composition to an elongation shear force. Mixing ofthe dispersed phase material and the adhesive material can be done byany method that results in a dispersion, preferably a fine dispersion,of the dispersed phase material in the adhesive material. For example,melt blending, solvent blending, or any other suitable physical methodthat is able to adequately blend the dispersed phase material and theadhesive material.

Melt blending devices include those that provide dispersive mixing,distributive mixing, or a combination of dispersive and distributivemixing. Both batch and continuous methods of melt blending can be used.Examples of batch methods include BRABENDER (using a BRABENDER PREPCENTER, available from C.W. Brabender Instruments, Inc.; SouthHackensack, N.J.) or BANBURY internal mixing and roll milling (usingequipment available from FARREL COMPANY; Ansonia, Conn.). After batchmixing, the dispersion created can be immediately quenched and storedbelow melting temperature for later processing, if desired.

Examples of continuous methods of mixing include single screw extruding,twin screw extruding, disk extruding, reciprocating single screwextruding, and pin barrel single screw extruding. The continuous methodscan include both distributive elements, such as cavity transfer mixers(e.g., CTM, available from RAPRA Technology, Ltd.; Shrewsbury, England),pin mixing elements, and static mixing elements, as well as dispersiveelements (e.g., MADDOCK mixing elements or SAXTON mixing elements) asdescribed in, for example, “Mixing in Single-Screw Extruders,” Mixing inPolymer Processing, edited by Chris Rauwendaal (Marcel Dekker Inc.: NewYork (1991), pp. 129, 176-177, and 185-186).

Examples of Methods of Forming the Polymeric Composition

The polymeric composition is subjected to elongating shear force,creating the elongated structures of the dispersed phase material. Theelongated structures can be formed by continuous forming methods,including hot melt coating, such as drawing or extruding the blendedcomposition out of a elongating shear force (e.g. a draw die, film die,or rotary rod die) and subsequently contacting the drawn adhesivecomposition to a substrate, for example, individual substrates or asubstrate on a moving web. A related continuous forming method includesco-extruding the polymeric composition and a backing material from afilm die and cooling the layered product. Other continuous formingmethods include directly contacting the polymeric composition to arapidly moving web or other suitable preformed substrate. Using thismethod, the polymeric composition can be applied to the moving preformedweb using a die having flexible die lips, such as a rotary rod die.

After formation by any of these continuous methods, the elongatedstructures of dispersed phase material can be solidified by lowering thetemperature of the polymeric composition to below the meltingtemperature of the dispersed phase material. The temperature can belowered by, for example, quenching the polymeric composition usingeither direct methods (e.g., chill rolls or water baths) or indirectmethods (e.g., air or gas impingement). The composition is then cooledto ambient temperature.

Optical Properties The index of diffraction difference between theadhesive material and the dispersed phase material and the orientationof the elongated structures of dispersed phase material provide thepolymeric composition with optical properties that differ from those ofthe adhesive material by itself. In particular, the alignment of theelongated structures of dispersed phase material produce preferentialscattering in directions perpendicular to the major axes of theelongated bodies. For example, for oriented fibers of dispersed phasematerial, the scattered light can appear as a band of light in the planeperpendicular to the orientation direction with an intensity thatdecreases with increasing angle away from the specular reflectiondirections.

A number of factors influence the optical properties of the polymericcomposition including, for example, the materials used for the adhesiveand dispersed phase components, the indices of refraction of theadhesive and dispersed phase materials, the degree of orientation of theelongated structures, the size and shape of the elongated structures,the thickness of the polymeric composition, the relative amounts ofdispersed phase material and adhesive material (i.e., the loading), theuniformity of the distribution of the elongated structures within thepolymeric composition, the relative positions and amounts of eachmaterial, and the presence of other materials (e.g., other scatteringmaterials, dyes, or pigments).

Generally, at least one index of refraction of the dispersed phasematerial differs by at least 0.01 from at least one index of refractionof the adhesive material. Total light scattering is dependent onrefractive index difference between the dispersed phase material and theadhesive material, as well as the number of elongated structures withinthe light path (loading and film thickness). The total scattering oflight is generally proportional to the square of refractive indexdifference between the two materials and linearly proportional to thenumber of scattering domains. The refractive index difference betweenthe adhesive material and the dispersed phase material is generally atleast 0.01, 0.03, 0.05, or more. In many instances, the total scatteringefficiency can be modeled as:total scattering efficiency ∝Δn²*t*w %,where Δn is the refractive index difference between the adhesivematerial and the dispersed phase material, t is the thickness of thepolymeric composition, and w % is the weight percent of the dispersedphase material. Thus, the amount of scattered light as a percentage oftransmitted or reflected light can be selected by choosing therefractive index difference, the thickness, and weight percent of thedispersed phase material. For some embodiments, the weight percent ofthe dispersed phase material is in the range of 5% to 50% and typicallyin the range of 10% to 40%. The thickness of the polymeric compositionaffects the light scattering efficiency as well as the adhesivemechanical strength. The thickness can be in the range of, for example,5 micrometers to 250 micrometers and is, in some embodiments, in therange of 50 micrometers to 125 micrometers.

In some embodiments, the adhesive material or the dispersed phasematerial (or both) is birefringent (i.e., the indices of refraction ofthe material differ by at least 0.01 in at least two orthogonaldirections). For example, a birefringent material formed in a planarlayer can have indices of refraction in the in-plane directions (chosenas the x- and y-directions) that are different (i.e., n_(x)≠n_(y)).Using such a birefringent material can result in polarization-dependentoptical properties. For example, the difference in optical indicesbetween the adhesive and dispersed phase materials, when at least onebirefringent material is used, can be different for two orthogonalpolarizations of light incident on the polymeric composition. The largerdifference in indices will typically result in larger angle scatteringand more scattering of light for one polarization. In at least someinstances, the ratio of the scattering power for the two polarizationsis the square of the differences in index of refraction between the twomaterials for each polarization. In one embodiment, a birefringentmaterial is used in which, for one polarization of light, the indices ofrefraction of the adhesive and dispersed phase materials substantiallymatch (i.e., differ by less than 0.01) so that light of thatpolarization is substantially transmitted through the polymericcomposition. For the other polarization of light, the indices ofrefraction of the adhesive and dispersed phase materials differ by atleast 0.01, resulting in the scattering of light having thatpolarization.

The degree of orientation of the elongated structures will also affectthe optical properties. Typically, a higher degree of orientation of theelongated structures will result in more preferential scattering oflight perpendicular to the major axes of the elongated structures. As anexample of orientational order, a polymeric composition can containelongated structures in which the major axes of at least 50%, 75%, oreven 90% of the elongated structures are substantially aligned (e.g.,aligned within 20°, and preferably within 10°, of each other) over thelength of the elongated structures.

The size and shape of the elongated structures will also influence theoptical properties. For example, diffuse reflection will be obtainedwhen the cross-sectional dimension (e.g., diameter) of the elongatedstructures is no more than about several times the wavelength of lightincident on the polymeric composition. As the cross-sectional dimensionof the elongated structures increases, the amount of specular reflectionwill typically increase. In addition, longer elongated structurestypically have more light scattered in the preferential directions thando shorter elongated structures of the same material and cross-sectionaldimension. Thus, long fibers will tend to result in larger amounts ofdiffusely scattered light perpendicular to the length of the fibers.Shorter rods of material will typically result in less preferentialscattering in the perpendicular directions.

The three-dimensional shape and size of the elongated structures affecthow the scattering light is distributed into spatial directions. Forspherical particles, the distribution of the light scattering issymmetric around the optical axis, which is defined as the axis ofincident light. If the particles are non-spherical, light scatteringwill generally be distributed asymmetrically around the optical axis.Typically, light scattering is spread more widely in the plane where thecross section of the particles is more curved. For particles withellipsoidal cross section, light is spread more around the longer axisthan around the shorter axis. The degree of asymmetry is dependent onthe aspect ratio of the particles (how far the cross section is awayfrom a circle). For fibers, light is preferentially scattered in thedirection normal to the orientation of the fibers. In the directionparallel to the fiber orientation, the polymeric composition acts as anoptical parallel plate. Therefore, little light will be scattered. Thefilm resembles a uniaxial light diffuser. For the best effect, thefibers preferably have an aspect ratio of at least 50, 100, or even 1000or more. For elongated particles with a smaller aspect ratio, the crosssection of the particles is more likely to be ellipsoid. In this case,some of the light will be scattered into the direction parallel to thefiber orientation. Such fibers act as ellipsoid diffusers. Combining apolymeric composition with high aspect ratio fibers with a weaksymmetric diffuser element containing spherical particles can also makean ellipsoid diffuser.

FIGS. 4 and 5 illustrate the optical properties of high aspect ratiofibers. When the elongated structures form fibers or filaments, thesestructures can be very long in comparison to their cross-sectionaldimension. The optical properties of these structures can be modeledusing an array of cylinders each having infinite length. Referring toFIG. 4, a cross-sectional view through the major axis of a single fiber404 from such an array is shown embedded in the adhesive material 402. Alight ray 401 that is normally incident on the surface 406 of theadhesive material 402 is refracted by non-normal incidence on the fiber404, as illustrated at point A of FIG. 4. The angle of refraction willtypically depend on the distance x from the center of fiber 404 at whichray 401 is incident on fiber 404. Further refraction occurs as the lightray exits the fiber 404 (point B) and as the light ray exits theadhesive material 402 at surface 408 (point C). The angle of theserefractions will be dependent on the previous refraction(s). As aresult, different rays are refracted by different amounts, therebyproducing a diffusion effect on incident light. Referring to FIG. 5,which shows the longitudinal view of fiber 404 along the major axis,normally incident ray 401 does not undergo refraction in thelongitudinal plane, since the ray is normally incident on the surfacesof the adhesive material 402 and the fiber 404. Thus, a highlyanisotropic diffusion effect is produced. As a result of this asymmetricdiffusion effect, the materials of the present invention are useful inrear projection screens, where, for example, a high level of diffusionin the horizontal direction can be desirable, in order to reach moreviewers, but a lower level of diffusion in the vertical direction can bedesirable in order to conserve light by not directing it to locationswhere no viewers are present.

Thicker layers of the polymeric composition will typically result inmore light scattering for a given loading of dispersed phase materialand type of elongated structures. For some adhesive tape applications,the thickness of the polymeric composition on a suitable substrate canrange from 25 to 750 μm. A higher loading of dispersed phase materialwill also typically increase the scattering.

Furthermore, the uniformity of the distribution of the elongatedstructures within the polymeric composition will affect the uniformityof the scattering. Typically, the dispersed phase material is uniformlydispersed within the adhesive material. However, if desired, thedispersed phase material can be non-uniformly distributed using knowntechniques to obtain non-uniform light scattering.

The presence of additional non-oriented (e.g., spherical or randomlyoriented) scattering material will also influence the optical propertiesof the polymeric composition. The non-oriented scattering material canbe used to adjust the ratio of light scattering in the preferred andnon-preferred directions. In addition, the presence of a coloringmaterial, such as a dye or pigment, can alter the color of the polymericcomposition to add or reduce color, as described above.

The polymeric composition typically appears transparent, translucent, orslightly to moderately hazy. The appearance will depend on the adhesiveand dispersed phase materials, as well as the amount of the dispersedphase material in the composition and the morphology of the elongatedstructures.

When polarized light is incident on the polymeric composition, thedispersed phase can produce some depolarization due to scattering.Typically, the depolarization is less for elongated structures withsmaller cross-sectional dimensions. Therefore, it is possible to designdiffusive films that maintain high extinction polarization ratios whilescattering linearly polarized light.

Physical Properties

The physical properties of the polymeric composition are, at least inpart, a result of the materials selected for the adhesive and dispersedphase components, as well as the structure of the dispersed phasematerial within the polymeric composition. In some embodiments, thepolymeric composition has a yield strength that is no less than about0.1 MPa when measured by ASTM D 882-97. The yield strength can be 0.2MPa or more. Additionally, the polymeric composition can have a tensilestrength of at least about 150% of the yield strength when measured byASTM D 882-97.

For some embodiments, the elongation at break for the polymericcomposition is at least about 50% when measured by ASTM D 882-97, andcan be more than about 200% or even 300% or more. In some embodiments,the elongation at break is 800% or more.

Additionally, in some embodiments of pressure sensitive adhesivecompositions, the amount of force required to remove the polymericcomposition from a polypropylene substrate panel at an angle of between15° and 35°, is no more than about 20 N/dm. This low removal forcepermits facile removal of the pressure sensitive adhesive compositionfrom a substrate. In certain embodiments, the force necessary to removethe pressure sensitive adhesive composition from a substrate at such anangle is as low as about 7 N/dm.

The polymeric composition can, in some embodiments, have a tensilestrength of at least about 2 times greater than the tensile strength ofthe adhesive material alone when measured according to ASTM D 882-97. Incertain embodiments, the dispersed phase material increases the peelforce of the adhesive material in the machine direction. For example,the 180° peel adhesion force for a polymeric composition adhered to aparticular substrate (e.g., glass) can be increased by 30% or more ascompared to the 180° peel adhesion force of the adhesive materialwithout the dispersed phase material.

Additionally, the polymeric composition can have stretch removableproperties. In some embodiments, the polymeric composition of theinvention can have these properties with substantially unreduced tackproperties, if desired.

For those embodiments with good yield and tensile strength, thepreferred dispersed phase materials have a yield strength of no morethan about 20 MPa. The tensile strength of the dispersed phase materialwith respect to its yield strength is preferably about 150% of the yieldstrength. These values are measured using ASTM D 882-97.

Applications of the Polymeric Compositions The polymeric composition canbe used for a variety of applications. For example, the polymericcomposition can be applied to sheeting products (e.g., decorative,reflective, and graphical products), labelstock, tape backings, andother polymeric or non-polymeric substrates to form, for example,decorative tapes and optical films for display applications. Thepolymeric composition can also be used for light extractionapplications, such as signage, advertising, and lighting. Examples oflight extraction applications include the disposition of the polymericcomposition, typically with a substrate backing, on a light emittingdiode (LED), organic light emitting device (OLED), luminescence film, orfluorescence film. With respect to displays, the polymeric compositiondisposed on a transparent substrate can be used as a display film with,for example, projection displays to provide a narrow viewing angle inone direction (vertical, for example) and a broad viewing angle inanother direction (horizontal, for example).

The substrate can be any suitable type of material depending on thedesired application. For example, the substrate can includepolypropylene (e.g., biaxially oriented polypropylene (BOPP)),polyethylene, polyester (e.g., polyethylene terephthalate), otherpolymeric and plastic substrates, or a release liner (e.g., asiliconized liner). In some embodiments, particularly where the articlecontaining the polymeric composition is designed to be removable, thesubstrate is stretchable so that an article containing the adhesivecomposition and a substrate is stretch removable. The substrate istypically, but not necessarily, transparent or translucent, particularlyif the scattered light travels through the substrate prior to or afterscattering by the dispersed phase material. Colored substrates can alsobe used, if desired. The surface of the substrate opposite the polymericcomposition or the surface of the polymeric composition itself can beembossed, microstructured, or otherwise altered to provide a desiredtexture, which can also alter the optical properties of the article. Forexample, the altered surface can increase diffusive scattering of light.

As an example, a polymeric composition according to the presentinvention can be utilized to form tape or other adhesive film. To form atape, the polymeric composition is coated onto at least a portion of asuitable substrate. A release liner (e.g., low adhesion backing) can beapplied to the opposite side of the polymeric composition from thesubstrate, if desired. When double-coated tapes are formed, thepolymeric composition is coated, for example by co-extrusion orlamination, onto at least a portion of both sides of the substrate.Additionally, the polymeric composition can be coated on at least onerelease liner to form a transfer tape or film.

Another application of the polymeric composition is to assist incoupling light out of a light containing medium, as illustrated in FIGS.2 and 3. The light containing medium 200, 300 can be, for example, afilm (e.g., a luminescence or fluorescence film), a device (e.g., a LEDor OLED), or an optical fiber, plate, or other light conductingstructure. Light can be trapped within these light containing media dueto total internal reflection. This occurs when the light 310 (FIG. 3)within the light containing medium is reflected at the interface 312(FIG. 3) between the light containing medium and another medium, such asair.

In some instances, total internal reflection is desired, particularlyfor light traveling down a light guide, such as an optical fiber oroptical plate. The optical fiber or optical plate can have any shape orgeometry and can be made from any appropriate material including, forexample, glass and plastic. It can be desirable to selectively extractlight from certain portions of the optical fiber or plate or to extractlight from the entire light guide. For example, a light guide can beshaped in the form of letters, symbols, or images and it can bedesirable to extract light along portions of the length of the lightconducting medium to produce an illuminated letter, letters, word, othertext, a symbol or symbols, an image, or any other shape. The extractedlight can be used, for example, to form signs or advertisements orprovide lighting. In addition, the extracted light can be colored by,for example, using a colored light source or by providing a dye orpigment to the polymeric composition.

A light guide, such as an optical fiber or plate, whose index ofrefraction is higher than the surrounding medium can transmit lightefficiently based on total internal reflection. Light constrained insidethe light guide is found in discrete modes. The number of modes isdependent on the index difference between the light guide and thesurroundings and the thickness or diameter of the light guide. With moremodes, light can be transmitted through the light guide along a largercone of angles. Each mode has a different spatial position through thelight guide. Modes with higher numbers typically have a larger incidenceangle at the boundary of the light guide. More efficient light couplingand transmission is obtained by using a high refractive index differenceand large light guides. For the most efficient light extraction, lightconstrained inside the light guide is preferably in the higher numbermodes where more light is distributed close to the boundary of the lightguide. This can happen by purposely coupling more light into the highermodes of the light guide or by bending the light guide to redistributethe light into higher modes.

In some instances, total internal reflection is problematic. Forexample, significant portions of light can be trapped inside an LED,OLED, luminescence film, fluorescence film, or other light-emitting filmor device by total internal reflection. Light is lost through the edgesof the device or film.

A film made using the polymeric composition and, optionally, a suitablesubstrate can be used to extract light from these devices and films. Thefilm 202, 302 containing the polymeric composition is positioned on theportion of the device or film from which light is to be extracted.Typically, the polymeric composition is selected to have a refractiveindex that is close to the refractive index of the device or film.Typically, the difference between the refractive indices of the adhesivematerial of the polymeric composition and the device or film is no morethan 0.15, and can be 0.1 or 0.05 or less. Because the refractiveindices are close, light 314 (FIG. 3) can be coupled into the polymericcomposition. Generally, the closer the indices of refraction of theadhesive material and the device or film, the more light that can beextracted.

The light that enters the polymeric composition from the device or filminteracts with the dispersed phase material 316 (FIG. 3) so that thelight is scattered and at least a portion of the light is scattered outof the film. In addition, because of the alignment of the elongatedstructures (as illustrated by arrows 216 of FIG. 2 and the orientationof the dispersed phase material 306 of FIG. 3) of the dispersed phasematerial, the light 208, 308 is extracted anisotropically inpreferential directions, as discussed above. As illustrated in FIGS. 2and 3, the polymeric composition can be disposed over an entire portionof a surface, for example, around an entire portion of an optical fiber,or only over a restricted portion of the surface. The disposition of thepolymeric composition and the orientation of the elongated structures ofdispersed phase material will typically determine where and how muchlight is extracted. In some embodiments, the light emitted from the filmor device at the point where the polymeric composition is disposed canbe at least two, three, or even four times the light emitted without thepolymeric composition.

When light travels in a direction along a light guide, the orientationof the elongated structures with respect to the travel direction impactsthe amount of scattering. The most scattering is obtained when the majoraxes of the elongated structures are oriented perpendicularly to thelight travel direction. Moreover, since light incident onto the filmcontaining the polymeric composition has a certain angle to the normalof the film surface, the scattering light distribution will also not besymmetrically distributed around the normal to the film surface. Rather,the scattering light is typically distributed toward the end other thanthe coupling end. Usually, light in coupled from a light source intowave guide from one end. This end can be called the “coupling end”. Fortotal reflection, the light incident on the boundary has to have theincident angle larger than the critical angle. When an adhesive film isapplied onto the wave guide, the light incident onto the film has largeincident angle (as away from the surface normal). The diffused light iscentered around the incident light axis. Therefore, the distribution ofthe diffused light will not be centered around the surface normal,rather it is centered on the incident light axis direction, which istilted to the other end of the wave guide (opposite of the couplingend). By placing a reflection mirror on the other end to reflect backsome of the light, the distribution of scattering light will become moresymmetrically around the surface normal direction.

In some embodiments, a device or film includes an electrode or otherelement made of a reflecting material, such as a metal (e.g., silver oraluminum). The disposition of the polymeric composition over the deviceor film can also reduce or diffuse at least a portion of the specularreflection from the reflecting material.

In some embodiments, a tape, film, or other article can be formed havingdomains with different elongated structure orientation. Such films canbe formed, for example, by dispensing the polymeric composition indifferent directions on the substrate or attaching preformed polymericcompositions with the elongated structures in the desired orientations(e.g., transferring polymeric compositions using a transfer tape). Thedifferent domains can contain the same or different dispersed phasematerial, dispersed phase material loading, thickness, degree ororientation, and elongated structure shape and size. Such embodimentscan be used for decorative purposes, to form images, symbols, letters,or words, and other applications.

Moreover, two or more films can be used to control or enhance the lightscattering. For example, two or more films can be applied to a surfacewith different elongated structure alignment directions to scatter lightinto a variety of preferential or predetermined directions.

The polymeric composition, typically in the form of a film, can be usedwith a variety of other optical components. Examples of such componentsincludes other optical films, lenticular diffusers, symmetric or bulkdiffusers, mirrors, color films or filters, and beam splitters.

The polymeric composition, typically in the form of a film, can be usedwith front or rear projection screens, such as those used in front orrear projection monitors, televisions, and other devices. The film istypically placed over the screen and used to adjust the horizontal orvertical viewing angle or both. The film can also be used with (e.g.,laminated to) an absorption polarizer to reduce ambient light backgroundand increase contrast ratio for rear projection screens. Such aconfiguration can also be used for backlight or frontlight illuminationof liquid crystal displays. The film can be used with (e.g., laminatedto) a mirror for use with front projection screens.

As a further example, for some lighting applications, a small number oflight sources is desired, for example, for safety or maintenance. Inthis case, light from one light source can be coupled into a large-coreoptical fiber and delivered to multiple locations. Efficienttransmission is desired along the optical fiber except in the locationswhere illumination is needed. The films described above can be used forthis purpose. Only in the locations where the film is applied will lightbe coupled out of the optical fiber. Light is efficiently deliveredalong the portions of the fiber where no adhesive film is applied.

The optical properties of the materials of the present invention areparticularly suitable for managing light in an optical system. Thematerials may be used as a portion of a component in the optical systemor as a stand alone element. Optical systems that may include materialsaccording to the present invention include emissive devices such aselectroluminescent (EL) devices, organic electroluminescent devices(OLED), inorganic light emitting diodes (LED), phosphor-basedbacklights, phosphor based direct view displays such as cathode raytubes (CRT) and plasma display panels (PDP), field emission displays(FED), and the like. The system may be a projection display, a backlitdisplay or a direct view display. The system can emit white light,monochrome color light, multiple colors, or full color (e.g. RGB, orred, green, blue); and it can also be a segmented (e.g., low resolution)or a pixilated (e.g. high resolution) display.

The articles described herein can also be used in a liquid crystaldisplay. For example, the articles may be especially useful as adiffusive element in the liquid crystal display.

Referring now to FIG. 11, there is shown an optical system 500 that mayutilize the materials of the present invention as at least a componentthereof. The optical system 500 comprises a front projection screen 502and a light source 504.

The materials described above may be utilized as the front projectionscreen 502 itself or as a component of a front projection screen. FIG.12 illustrates one embodiment of front projection screen wherein thematerials of the present invention form a diffuser 510. The screen shownin FIG. 12 also includes optional polarizer 514 and reflector 512. Forexample, the polarizer 514 may comprise a linear polarizer. Thepolarizer 514 may be used for a variety of reasons. For example, thepolarizer may be utilized to reduce ambient light reflected from thescreen.

FIG. 13 illustrates another embodiment of front projection screen. Thematerials according to the present invention form a diffuser 520. Thescreen also includes a reflector 522 to reflect light from the lightsource 504.

Referring now to FIG. 14, there is shown another optical system 600 thatmay utilize materials of the present invention as at least a componentthereof. The optical system 600 comprises a rear projection screensystem with an illumination source 602, an optional fresnel structure604 and a rear projection screen 606. The optical system 600 maycomprise many different types of products, such as, but not limited to,televisions, video walls, large screen TV's, and data monitors. Thematerials according to the present invention may be utilized toconstruct the screen 606 itself, or may form a component thereof.

The illumination source 602 projects an image toward screen 606. Thescreen 606 has a rear side that receives light originating fromillumination source 602 and a front side or viewing side. In use, theviewer looks at the front side of the screen 606 to see the imageprovided by the optical system 600.

The optical system 600 may include an optional fresnel lens 604 and/or alenticular lens or sheet as described or constructed in accordance withU.S. Pat. Nos. 3,712,707; 3,872,032; 4,379,617; 4,418,986; 4,468,092;4,469,402; 4,509,823; 4,548,469; 4,576,850; 4,730,897; 4,773,731;5,066,099, 5,183,597; 5,296,922 and 5,513,036 (the entire contents ofwhich are herein incorporated by reference). Methods of makinglenticular or fresnel structures are described in EP Pat. Appl. Nos. 542548 and 816 910 (incorporated by reference herein).

FIG. 15 illustrates one embodiment of screen 606A according to thepresent invention. The materials according to the present invention maybe utilized to provide a diffuser 614 for the screen 606A. The screen606A may also include a lenticular structure 612 and a polarizer 616.The polarizer 616 may be used for a variety of reasons. For example, thepolarizer 616 may be utilized to reduce ambient light reflected from thescreen in order to increase the desirable contrast characteristics ofthe screen. The polarizer 616 may also be used as a clean up polarizerfor the optical system. As another example, the polarizer 616 may be alinear polarizer constructed in accordance with the teachings of U.S.Pat. No. 6,163,402 (the entire contents incorporated by referenceherein).

FIG. 16 illustrates another embodiment of screen 606B according to thepresent invention. In this embodiment, the materials of the presentinvention may be utilized to provide a diffuser 624. The screen 606Balso includes a lenticular element 622.

FIG. 17 illustrates another embodiment of screen 606C according to thepresent invention. In this embodiment, the materials of the presentinvention may be utilized to provide a diffuser 632. The screen 606Calso includes a polarizer 634 such as a linear polarizer.

EXAMPLES

This invention is further illustrated by the following examples that arenot intended to limit the scope of the invention. These examples aremerely for illustrative purposes only and are not meant to be limitingon the scope of the appended claims. All parts, percentages, ratios,etc. in the examples and the rest of the specification are by weightunless indicated otherwise. All UV curing of an adhesive describe in theexamples took place adhesive side toward the UV. Pressure sensitiveadhesive is abbreviated “PSA” in the following examples. Table ofAbbreviations Abbreviation Description AA Acrylic acid ATTANE 4202 UltraLow Density Linear Polyethylene-co-octene copolymer derived from 10%octene, commercially available from Dow Chemical Co.; Midland, MI.Refractive index is approximately 1.52 CV-60 A Mooney viscositycontrolled natural rubber, available from Goodyear Chemical; Akron, OH.ENGAGE 8200 Ethylene-octene copolymer derived from 24% octene,commercially available from DuPont Dow Elastomers LLC; Wilmington, DE.ENGAGE 8490 Ethylene-octene copolymer derived from 14% octene,commercially available from DuPont Dow Elastomers LLC; Wilmington, DE.ESCOREZ 2393 Aliphatic/aromatic mixed tackifier resin commerciallyavailable from ExxonMobil Chemical; Houston, TX. HDPE High DensityPolyethylene, having an average molecular weight of 125,000 and adensity of 0.95 grams/cubic centimeter, commercially available fromScientific Polymer Products, Inc.; Ontario, NY. IOA Iso-octyl acrylateKRATON D1107 Styrene-isoprene-styrene block copolymer commerciallyavailable from Shell Chemicals Ltd.; Houston, TX. LDPE Low densitypolyethylene, having a density of 0.918 grams/cubic centimeter,commercially available from Aldrich Chemical Co.; Milwaukee, WI. MAAMethacrylic acid PB Isotactic Polybutene, having a weight averagemolecular weight of 185,000, commercially available from AldrichChemical Co.; Milwaukee, WI. Refractive index is approximately 1.50 PCLPolycaprolactone, having a weight average molecular weight of 80,000,commercially available from Aldrich Chemical Co.; Milwaukee, WI. PEBHMetallocene catalyzed poly(ethylene-co-1-butene-co-1-hexene), with amelt index of 3.5, commercially available from Aldrich Chemical Co.;Milwaukee, WI. Refractive index is approximately 1.51. PET Anaminated-polybutadiene primed polyester film of polyethyleneterephthalate having a thickness of 38 micrometers. PMMAPolymethylmethacrylate, having a weight average molecular weight of350,000 commercially available from Aldrich Chemical Co.; Milwaukee, WI.Refractive index is approximately 1.43 PP substrate Polypropylenesubstrate commercially available from Aeromat Plastics Inc.; Burnsville,MN. PS Polystyrene, having a weight average molecular weight of 280,000,commercially available from Aldrich Chemical Co.; Milwaukee, WI.Refractive index is approximately 1.59. PSA-1 IOA/AA copolymer PSA,derived from an approximate ratio of IOA/AA monomers of 90/10 preparedby mixing 21.6 grams of IOA, 2.4 grams of AA, 0.28 grams of carbontetrabromide chain transfer agent and 36 grams of ethyl acetate in aglass vessel. To this mixture 0.072 grams of VAZO 64 was added, thevessel was made inert with nitrogen gas and sealed. The sealed bottlewas tumbled in a 55° C. water bath for 24 hours. The resultant polymerwas coated on a siliconized polyester release liner, and oven dried for15 minutes at 65° C. to recover the dried polymer. PSA-2 Pressuresensitive adhesive containing a mixture of 50 parts of KRATON D1107 and50 parts of WINGTACK PLUS. PSA-3 Kraton PSA HL-2552X, commerciallyavailable from HB Fuller; St. Paul, MN. PSA-4 IOA/MAA copolymer PSAderived from an approximate ratio of IOA/MAA monomers of 96/4 preparedas described in U.S. Pat. No. 4,952,650 (Young, et al), Example 5 anddried prior to use. Refractive index is approximately 1.47. PSA-5 IOA/AAcopolymer PSA, derived from an approximate ratio of IOA/AA monomers of90/10 polymerized as described in U.S. Pat. No. 5,804,610 (Hamer, etal), Example 1 with the exception that the pouch was removed prior tofeeding the PSA into the extruder. PSA-6 IOA/AA copolymer PSA graftedderived polystyrene macromer, with an approximate ratio ofIOA/AA/polystyrene monomers of 92/4/4 prepared as described in U.S. Pat.No. 4,554,324 (Husman, et al), Example 74 except that the macromer waspolystyrene and the inherent viscosity was 0.65 dl/g (measured inethylacetate at 27° C.) Refractive index is approximately 1.48. PSA-7PSA-6 blended with 23% ESCOREZ 2393 tackifier. PSA-8 IOA/AA copolymerPSA, derived from an approximate ratio of IOA/AA monomers of 95.5/4.5polymerized as described in U.S. Pat. No. RE 24,906 (Ulrich), Example 5,and dried prior to use. PSA-9 Natural rubber PSA prepared from CV-60 asdescribed in U.S. Pat. No. 6,063,838 (Patnode, et al) Examples 43-44.REGALREZ 1126 Hydrogenated tackifier resin commercially available fromHercules, Inc.; Wilmington, DE. WINGTACK PLUS A C5 tackifier resincommercially available from Goodyear Tire & Rubber Company; Akron, OH.Test MethodsTensile Testing

Tensile testing was carried out according to ASTM test method D 882-97“Standard Test Method for Tensile Properties of Thin Plastic Sheeting”using an INSTRON materials tester (commercially available from Instron;Canton, Mass.) at a crosshead speed of 30 centimeters/minute (12inches/minute). Using this test, the values for “Yield Strength”,“Tensile Strength”, and “Percent Elongation at Break” were obtained.

180° Peel Adhesion

This peel adhesion test is similar to the test method described in ASTMD 3330-90, substituting a glass, high density polyethylene orpolypropylene substrate for the stainless steel substrate described inthe test. The substrate used is noted in each particular example.

Adhesive-coated strips that had equilibrated at constant temperature(21° C.) and humidity (50% relative humidity) for at least 24 hours,were adhered to a substrate panel. The substrate panel was eithersolvent-washed glass, polypropylene (PP), or high density polyethylene(HDPE) using a 2 kilogram roller passed once over the strip. The bondedassembly was allowed to dwell at room temperature for one minute. Theassembly was then tested for 180° peel adhesion in the machine directionusing an IMASS slip/peel tester (Model 3M90, commercially available fromInstrumentors Inc., Strongsville, Ohio) at a crosshead speed of 30centimeters/minute (12 inches/minute).

Stretch Release Test Method

Adhesive-coated strips, which had equilibrated at constant temperature(21° C.) and humidity (50% relative humidity) for at least 24 hours,were adhered to a polypropylene (PP) substrate panel, using a 2 kilogramroller passed once over the strip. The bonded assembly was allowed todwell at room temperature for one minute. The assembly was then testedfor stretch release by pulling at an angle of between 15 and 35° either“by hand”, or “mechanically” using an IMASS slip/peel tester (Model3M90, commercially available from Instrumentors Inc., Strongsville,Ohio) at a crosshead speed of 30 centimeters/minute (12 inches/minute).The data are reported for the by hand samples as “broke” if the samplebroke before detachment (i.e. the sample did not stretch release), or“yes” if the sample exhibited stretch release properties. For themechanically tested samples, the data is reported as “broke” if thesample broke (i.e. the sample did not stretch release), or, if thesample did exhibit stretch release properties, the maximum stretchrelease force in Newtons/decimeter is reported.

Probe Tack Test

Probe tack measurements were made following the test method described inASTM D 2979-95 using a TA-XY2 texture tester (commercially availablefrom Stable Microsystems, Surrey, U.K.).

Solvent Extraction Test

To determine the continuity of the dispersed phase material of theadhesive composition, the pressure sensitive adhesive matrix wasdissolved, leaving behind the dispersed phase material. A strip of theadhesive composition film (approximately 7.5 centimeters long by 2.5centimeters wide) was cut from the film in the machine direction. Thestrip was suspended on an open frame by looping the film over the edgeof the open frame. The frame and adhesive strip were immersed in asolvent capable of dissolving the pressure sensitive adhesive but notthe dispersed phase material. After 24 hours the sample was checked todetermine if the pressure sensitive adhesive had completely dissolvedand if the dispersed phase material remained on the frame. If fiberswere not continuous for at least 5 to 8 centimeters, nothing remained onthe frame. The samples were rated as “pass” if fibers remained on theframe, and “fail” if no fibers remained on the frame.

Tensile Properties of Dispersed Phase Material

Films of dispersed phase material were prepared by hot-press moldingeach dispersed phase material to a thickness of 102 micrometers. Thefilms were tested using the Tensile Testing method described above. Theresults are shown in Table 1. Additionally, the materials arecharacterized as being elastomeric (rebounds upon deformation) orplastic (deforms permanently). TABLE 1 Yield Strength Tensile StrengthPercent Elongation Plastic or Polymer (MPa) (MPa) at Break (%)Elastomeric PEBH 5.09 31.72 730 Elastomeric PCL 7.45 16.41 620Elastomeric ATTANE 4202 8.27 27.58 >800 Elastomeric HDPE 20.55 14.34 370Plastic PMMA 25.51 25.51 <10 Plastic

Comparative Example C1

A sample of the pressure sensitive adhesive PSA-1 was prepared and hotmelt coated between two release liners at 150° C. using a HAAKE singlescrew extruder (commercially available from Haake, Inc.; Paramus, N.J.)equipped with a draw die. The screw speed of the extruder was 75 rpm andthe draw ratio was 4. The resulting PSA film had a thickness of 127micrometers. The tensile properties of the PSA film were determined asdescribed in the tensile test method above. The results are shown inTable 2. A portion of the PSA film was laminated to a PET backing tomake a PSA tape. The resulting tape was passed below a Fusion H-bulblamp (commercially available from Fusion total ultraviolet Systems,Inc.; Gaithersburg, Md.) at a crosshead speed of 15 meters/minute for atotal ultraviolet dose of 300 milliJoules/cm². The tape was tested for180° Peel Adhesion from glass. The results are shown in Table 3.

Comparative Example C2

A mixture of 90 parts PSA-1, 10 parts ENGAGE 8200 and 0.2 partbenzophenone was prepared in a BRABENDER mixer (commercially availablefrom C.W. Brabender Instruments, South Hackensack, N.J.) at 140° C. to150° C. for 8 to 10 minutes. The resulting mixture was hot melt coatedbetween two release liners at 150° C. using a HAAKE single screwextruder (commercially available from Haake, Inc.; Paramus, N.J.)equipped with a draw die. The screw speed of the extruder was 75 rpm andthe draw ratio was 4. The resulting PSA film had a thickness of 127micrometers. The tensile properties of the film were determined asdescribed in the tensile test method above. The results are shown inTable 2. A portion of the PSA film was laminated to a PET backing tomake a tape. The resulting tape was passed below a Fusion H-bulb lamp(commercially available from Fusion total ultraviolet Systems, Inc.;Gaithersburg, Md.) at a crosshead speed of 15 meters/minute for a totalultraviolet dose of 300 milliJoules/cm². The tape was tested for 180°Peel Adhesion from glass. The results are shown in Table 3.

Comparative Example C3

A mixture of 90 parts PSA-1, 10 parts of LDPE and 0.2 part benzophenonewere mixed in a BRABENDER mixer (commercially available from C.W.Brabender Instruments, South Hackensack, N.J.) at 140° C. to 150° C. for8 to 10 minutes. The resulting mixture was hot melt coated between tworelease liners at 150° C. using a HAAKE single screw extruder(commercially available from Haake, Inc.; Paramus, N.J.) equipped with adraw die. The screw speed of the extruder was 75 rpm and the draw ratiowas 4. The resulting film had a thickness of 127 micrometers. Thetensile properties of the film were determined as described in theTensile Test method above. The results are shown in Table 2. A portionof the film was laminated to a PET backing to make a tape. The resultingtape was passed below a Fusion H-bulb lamp (commercially available fromFusion total ultraviolet Systems, Inc.; Gaithersburg, Md.) at acrosshead speed of 15 meters/minute for a total ultraviolet dose of 300milliJoules/cm². The tape was tested for 180° Peel Adhesion from glass.The results are shown in Table 3.

Example 1

A mixture of 90 parts PSA-1, 10 parts ENGAGE 8490 and 0.2 partbenzophenone were mixed in a BRABENDER mixer (commercially availablefrom C.W. Brabender Instruments, South Hackensack, N.J.) at 140° C. to150° C. for 8 to 10 minutes. The resulting mixture was hot melt coatedbetween two release liners at 150° C. using a HAAKE single screwextruder (commercially available from Haake, Inc.; Paramus, N.J.)equipped with a draw die. The screw speed of the extruder was 75 rpm andthe draw ratio was 4. The resulting film had a thickness of 127micrometers. The tensile properties of the film were determined asdescribed in the Tensile Test method above. The results are shown inTable 2. A portion of the film was laminated to a PET backing to make atape. The resulting tape was passed below a Fusion H-bulb lamp at acrosshead speed of 15 meters/minute for a UV dose of 300milliJoules/cm². The tape was tested for 180° Peel Adhesion from glass.The results are shown in Table 3.

Example 2

A mixture of 90 parts PSA-1, 10 parts of ATTANE 4202 and 0.2 partbenzophenone were mixed in a BRABENDER mixer (commercially availablefrom C.W. Brabender Instruments, South Hackensack, N.J.) at 140° C. to150° C. for 8 to 10 minutes. The resulting mixture was hot melt coatedbetween two release liners at 150° C. using a HAAKE single screwextruder (commercially available from Haake, Inc.; Paramus, N.J.)equipped with a draw die. The screw speed of the extruder was 75 rpm andthe draw ratio was 4. The resulting film had a thickness of 127micrometers. The tensile properties of the film were determined asdescribed in the Tensile Test Method above. The results are shown inTable 2. A portion of the film was laminated to a PET backing to make atape. The resulting tape was passed below a Fusion H-bulb lamp(commercially available from Fusion total ultraviolet Systems, Inc.;Gaithersburg, Md.) at a crosshead speed of 15 meters/minute for a UVdose of 300 milliJoules/cm². The tape was tested for 180° Peel Adhesionfrom glass. The results are shown in Table 3. TABLE 2 Tensile PercentYield Strength Strength Elongation at Example (MegaPascals)(MegaPascals) Break (%) C1 0.04 0.06 >800 C2 0.18 0.65 >800 C3 1.19 1.59320 1 0.33 1.70 760 2 0.54 2.05 700

TABLE 3 Example 180° Peel Adhesion (N/dm) C1 57.8 C2 52.1 C3 61.9 1 95.02 88.4

Comparative Example C4

A sample of PSA-1 was hot melt coated between two release liners at 150°C. using a HAAKE single screw extruder (commercially available fromHaake, Inc.; Paramus, N.J.) equipped with a draw die. The screw speed ofthe extruder was 75 rpm and the draw ratio was 4. The resulting film hada thickness of 127 micrometers and was laminated to a PET backing tomake a tape. The resulting tape was passed below a Fusion H-bulb lamp(commercially available from Fusion total ultraviolet Systems, Inc.;Gaithersburg, Md.) at a crosshead speed of 15 meters/minute for a UVdose of 300 milliJoules/cm². The tape was tested for 180° Peel Adhesionfrom glass in the machine and the cross-web directions. The results areshown in Table 4.

Example 3

A mixture of 90 parts PSA-1 and 10 parts of ATTANE 4202 were mixed in aBRABENDER mixer (commercially available from C.W. Brabender Instruments,South Hackensack, N.J.) at 140° C. to 150° C. for 8 to 10 minutes. Theresulting mixture was hot melt coated between two release liners at 150°C. using a HAAKE single screw extruder (commercially available fromHaake, Inc.; Paramus, N.J.) equipped with a draw die. The screw speed ofthe extruder was 75 rpm and the draw ratio was 4. The resulting film hada thickness of 127 micrometers and was laminated to a PET backing tomake a tape. The resulting tape was passed below a Fusion H-bulb lamp(commercially available from Fusion total ultraviolet Systems, Inc.;Gaithersburg, Md.) at a crosshead speed of 15 meters/minute for a UVdose of 300 milliJoules/cm². The tape was tested for 180° Peel Adhesionfrom glass in the machine and the cross-web directions. The results areshown in Table 4. TABLE 4 180° Peel Adhesion in 180° Peel Adhesion inCross- Example Machine Direction (N/dm) web Direction (N/dm) C4 81.465.9 3 128.9 141.3

Comparative Example C5

A sample of PSA-1 was hot melt coated between two release liners at 150°C. using a HAAKE single screw extruder (commercially available fromHaake, Inc.; Paramus, N.J.) equipped with a draw die. The screw speed ofthe extruder was 50 rpm and the draw ratio was 8. The resulting film hada thickness of 51 micrometers and was laminated to a PET backing to makea tape. The resulting tape was passed below a Fusion H-bulb lamp(commercially available from Fusion total ultraviolet Systems, Inc.;Gaithersburg, Md.) at a crosshead speed of 15 meters/minute for a UVdose of 300 milliJoules/cm². The tape was tested for 180° Peel Adhesionfrom glass in the machine and cross-web directions. The results areshown in Table 5.

Comparative Example C6

A mixture of 90 parts PSA-1 and 10 parts of LDPE were mixed in aBRABENDER mixer (commercially available from C.W. Brabender Instruments,South Hackensack, N.J.) at 140° C. to 150° C. for 8 to 10 minutes. Theresulting mixture was hot melt coated between two release liners at 150°C. using a HAAKE single screw extruder (commercially available fromHaake, Inc.; Paramus, N.J.) equipped with a draw die. The screw speed ofthe extruder was 50 rpm and the draw ratio was 8. The resulting film hada thickness of 51 micrometers and was laminated to a PET backing to makea tape. The tape was tested for 180° Peel Adhesion from glass in themachine and cross-web directions. The results are shown in Table 5.

Example 4

A mixture of 90 parts PSA-1 and 10 parts of ATTANE 4202 were mixed in aBRABENDER mixer (commercially available from C.W. Brabender Instruments,South Hackensack, N.J.) at 140° C. to 150° C. for 8 to 10 minutes. Theresulting mixture was hot melt coated between two release liners at 150°C. using a HAAKE single screw extruder (commercially available fromHaake, Inc.; Paramus, N.J.) equipped with a draw die. The screw speed ofthe extruder was 50 rpm and the draw ratio was 8. The resulting film hada thickness of 51 micrometers and was laminated to a PET backing to makea tape. The resulting tape was passed below a Fusion H-bulb lamp(commercially available from Fusion total ultraviolet Systems, Inc.;Gaithersburg, Md.) at a crosshead speed of 15 meters/minute for a UVdose of 300 milliJoules/cm². The tape was tested for 180° Peel Adhesionfrom glass in the machine and cross-web directions. The results areshown in Table 5. TABLE 5 180° Peel Adhesion in 180° Peel Adhesion inCross-web Direction Example Machine Direction (N/dm) (N/dm) C5 54.9 51.4C6 36.7 63.0 4 96.9 88.4

Comparative Example C7

A sample of PSA-2 was hot melt coated between two release liners at 150°C. using a HAAKE single screw extruder (commercially available fromHaake, Inc.; Paramus, N.J.) equipped with a draw die. The screw speed ofthe extruder was 75 rpm and the draw ratio was 4. The resulting film hada thickness of 127 micrometers and was laminated to a PET backing tomake a tape. The tape was tested for 180° Peel Adhesion on varioussubstrates. The results are shown in Table 6.

Example 5

A mixture of 90 parts PSA-2 and 10 parts of ATTANE 4202 were mixed in aBRABENDER mixer (commercially available from C.W. Brabender Instruments,South Hackensack, N.J.) at 140° C. to 150° C. for 8 to 10 minutes. Theresulting mixture was hot melt coated between two release liners at 150°C. using a HAAKE single screw extruder (commercially available fromHaake, Inc.; Paramus, N.J.) equipped with a draw die. The screw speed ofthe extruder was 75 rpm and the draw ratio was 4. The resulting film hada thickness of 127 micrometers and was laminated to a PET backing tomake a tape. The tape was tested for 180° Peel Adhesion on varioussubstrates. The results are shown in Table 6. TABLE 6 180° Peel 180°Peel 180° Peel Adhesion Adhesion for Adhesion from PP Example from glass(N/dm) HDPE (N/dm) (N/dm) C7 181 79 156 5 238 91 231

Comparative Example C8

A sample of PSA-3 was used as obtained and hot melt coated between tworelease liners at 150° C. using a HAAKE single screw extruder(commercially available from Haake, Inc.; Paramus, N.J.) equipped with adraw die. The screw speed of the extruder was 75 rpm and the draw ratiowas 4. The resulting PSA film had a thickness of 127 micrometers and waslaminated to a PET backing to make a tape. The tape was tested for 180°Peel Adhesion on various substrates. The results are shown in Table 7.

Example 6

A mixture of 90 parts PSA-3 and 10 parts of ATTANE 4202 were mixed in aBRABENDER mixer (commercially available from C.W. Brabender Instruments,South Hackensack, N.J.) at 140° C. to 150C. for 8 to 10 minutes. Theresulting mixture was hot melt coated between two release liners at 150°C. using a HAAKE single screw extruder (commercially available fromHaake, Inc.; Paramus, N.J.) equipped with a draw die. The screw speed ofthe extruder was 75 rpm and the draw ratio was 4. The resulting film hada thickness of 127 micrometers and was laminated to a PET backing tomake a tape. The tape was tested for 180° Peel Adhesion on varioussubstrates. The results are shown in Table 7. TABLE 7 180° Peel 180°Peel 180° Peel Adhesion Adhesion from Adhesion from from Example glass(N/dm) HDPE (N/dm) PP (N/dm) C8  53 25 33 6 100 23 42

Comparative Example C9

A sample of PSA-4 was hot melt coated between two release liners at 150°C. using a HAAKE single screw extruder (commercially available fromHaake, Inc.; Paramus, N.J.) equipped with a draw die. The screw speed ofthe extruder was 50 rpm and the draw ratio was 8. The tensile propertiesof the PSA film were determined as described in the Tensile Testingmethod above. The results are shown in Table 8.

Comparative Example C10

A mixture of 85 parts PSA-4 and 15 parts of PS were mixed in a BRABENDERmixer (commercially available from C.W. Brabender Instruments, SouthHackensack, N.J.) at 140° C. to 150° C. for 8 to 10 minutes. Theresulting mixture was hot melt coated between two release liners at 150°C. using a HAAKE single screw extruder (commercially available fromHaake, Inc.; Paramus, N.J.) equipped with a draw die. The screw speed ofthe extruder was 50 rpm and the draw ratio was 8. The tensile propertiesof the film were determined as described in the Tensile Test methodabove. The results are shown in Table 8.

Comparative Example C11

A mixture of 85 parts PSA-4 and 15 parts HDPE were mixed in a BRABENDERmixer (commercially available from C.W. Brabender Instruments, SouthHackensack, N.J.) at 140° C. to 150° C. for 8 to 10 minutes. Theresulting mixture was hot melt coated between two release liners at 150°C. using a HAAKE single screw extruder (commercially available fromHaake, Inc.; Paramus, N.J.) equipped with a draw die. The screw speed ofthe extruder was 50 rpm and the draw ratio was 8. The tensile propertiesof the PSA film were determined as described in the Tensile Test methodabove. The results are shown in Table 8.

Example 7

A mixture of 85 parts PSA-4 and 15 parts of ATTANE 4202 were mixed in aBRABENDER mixer (commercially available from C.W. Brabender Instruments,South Hackensack, N.J.) at 140° C. to 150° C. for 8 to 10 minutes. Theresulting mixture was hot melt coated between two release liners at 150°C. using a HAAKE single screw extruder (commercially available fromHaake, Inc.; Paramus, N.J.) equipped with a draw die. The screw speed ofthe extruder was 50 rpm and the draw ratio was 8. The tensile propertiesof the PSA film were determined as described in the Tensile Test methodabove. The results are shown in Table 8.

Example 8

A mixture of 85 parts PSA-4 and 15 parts PEBH were mixed in a BRABENDERmixer (commercially available from C.W. Brabender Instruments, SouthHackensack, N.J.) at 140° C. to 150° C. for 8 to 10 minutes. Theresulting mixture was hot melt coated between two release liners at 150°C. using a HAAKE single screw extruder (commercially available fromHaake, Inc.; Paramus, N.J.) equipped with a draw die. The screw speed ofthe extruder was 50 rpm and the draw ratio was 8. The tensile propertiesof the film were determined as described in the Tensile Test methodabove. The results are shown in Table 8. TABLE 8 Tensile Percent YieldStrength Strength Elongation at Example (MegaPascals) (MegaPascals)Break (%) C9  0.03 0.14 >800 C10 1.79 1.79 <50 C11 1.72 2.07 180 7 1.213.38 >800 8 0.47 2.83 630

Examples 9-13

The mixtures for Examples 9-13 were prepared using PSA-5 with the levelof ATTANE 4202 shown in Table 9, were mixed in a BRABENDER mixer(commercially available from C.W. Brabender Instruments, SouthHackensack, N.J.) at 140° C. to 150° C. for 8 to 10 minutes. Theresulting mixture was hot melt coated between two release liners at 150°C. using a HAAKE single screw extruder (commercially available fromHaake, Inc.; Paramus, N.J.) equipped with a draw die. The screw speed ofthe extruder was 75 rpm and the draw ratio was 4. The tensile propertiesof the film were determined as described in the Tensile Testing methodabove. The results are shown in Table 9. TABLE 9 Level of ATTANE TensilePercent 4202 Yield Strength Strength Elongation at Example (weight %)(MegaPascals) (MegaPascals) Break (%) 9 5 0.21 0.90 610 10 10 0.52 1.79670 11 15 0.95 3.59 610 12 30 2.21 7.31 650 13 40 3.45 13.51 580

Examples 14-16 and Comparative Examples C12-C14

The mixtures for Examples 14-16 and Comparative Examples C12-C14 wereprepared using PSA-4 with 15 weight % of a polymer as shown in Table 10,were mixed in a BRABENDER mixer (commercially available form C.W.Brabender Instruments, South Hackensack, N.J.) at 140° C. to 150° C. for8 to 10 minutes. The resulting mixture was hot melt coated between tworelease liners at 150° C. using a HAAKE single screw extruder(commercially available from Haake, Inc.; Paramus, N.J.) equipped with adraw die to give a thickness of 51 micrometers. The screw speed of theextruder was 50 rpm and the draw ratio was 8. The stretch releaseproperties of the film were determined as described in the StretchRelease Test Method above. The results are shown in Table 10. TABLE 10Polymer Added Stretch Release “by Example (15 weight %) hand” C12 PMMABroke C13 PS Broke C14 HDPE Broke 14 ATTANE 4202 Yes 15 PEBH Yes 16 PBYes

Examples 17-22 and Comparative Example C15

The mixtures for Examples 17-22 and Comparative Example C15 wereprepared using PSA-4 with the level of ATTANE 4202 shown in Table 11,were mixed in a BRABENDER mixer (commercially available from C.W.Brabender Instruments, South Hackensack, N.J.) at 140° C. to 150° C. for8 to 10 minutes. The resulting mixture was hot melt coated between tworelease liners at 150° C. using a HAAKE single screw extruder(commercially available from Haake, Inc.; Paramus, N.J.) equipped with adraw die to give a thickness of 51 micrometers. The screw speed of theextruder was 50 rpm and the draw ratio was 8. The stretch releaseproperties of the film were determined as described in the StretchRelease Test Method above. The results are shown in Table 11. TABLE 11Level of ATTANE Stretch Release Example 4202 (weight %) Force (N/dm) C150 N/A (broke) 17 5  7.4 18 10 10.7 19 15 13.1 20 20 14.1 21 30 19.6 2240 22.1

Examples 23-25 and Comparative Example C16

The mixtures for examples 23-25 and Comparative Example C16 wereprepared using PSA-6 with the level of ATTANE 4202 shown in Table 12mixed in a BRABENDER mixer (commercially available from C.W. BrabenderInstruments, South Hackensack, N.J.) at 140° C. to 150° C. for 8 to 10minutes. The resulting mixture was hot melt coated between two releaseliners at 150° C. using a HAAKE single screw extruder (commerciallyavailable from Haake, Inc.; Paramus, N.J.) equipped with a draw die togive a thickness of 51 micrometers. The screw speed of the extruder was50 rpm and the draw ratio was 8. The stretch release properties of thefilm were determined as described in the Stretch Release Test Methodabove. The results are shown in Table 12. TABLE 12 Level of StretchRelease ATTANE 4202 Force Example (weight %) (N/dm) C16 0 Broke 23 5 9.0 24 10 10.3 25 20 14.3

Examples 26-27 and Comparative Example C17

The mixtures for Examples 26-27 and Comparative Example C 17 wereprepared using PSA-7 with the level of ATTANE 4202 shown in Table 13mixed in a BRABENDER mixer (commercially available from C.W. BrabenderInstruments, South Hackensack, N.J.) at 140° C. to 150° C. for 8 to 10minutes. The resulting mixture was hot melt coated between two releaseliners at 150° C. using a HAAKE single screw extruder (commerciallyavailable from Haake, Inc.; Paramus, N.J.) equipped with a draw die togive a thickness of 127 micrometers. The screw speed of the extruder was75 rpm and the draw ratio was 4. The stretch release properties of thefilm were determined as described in the Stretch Release Test Methodabove. The results are shown in Table 13. TABLE 13 Level of StretchRelease ATTANE 4202 Force Example (weight %) (N/dm) C17 0 Broke 26 10 9.0 27 20 19.8

Examples 28-30 and Comparative Example C18

The mixtures for Examples 28-30 and Comparative Example C18 wereprepared using PSA-6 with the level of ATTANE 4202 shown in Table 14mixed in a BRABENDER mixer (commercially available from C.W. BrabenderInstruments, South Hackensack, N.J.) at 140° C. to 150° C. for 8 to 10minutes. The resulting mixture was hot melt coated between two releaseliners at 150° C. using a HAAKE single screw extruder (commerciallyavailable from Haake, Inc.; Paramus, N.J.) equipped with a draw die togive a thickness of 51 micrometers. The screw speed of the extruder was50 rpm and the draw ratio was 8. The probe tack properties of the filmwere determined as described in the Probe Tack Test method above. Theresults are shown in Table 14. TABLE 14 Level of Probe Tack for 51ATTANE 4202 micrometer thick Example (weight %) sample (grams) C18 0 26128 5 262 29 10 229 30 20 279

Examples 31-32 and Comparative Example C19

The mixtures for Examples 31-32 and Comparative Example C19 wereprepared using PSA-7 with the level of ATTANE 4202 shown in Table 15mixed in a BRABENDER mixer (commercially available from C.W. BrabenderInstruments, South Hackensack, N.J.) at 140° C. to 150° C. for 8 to 10minutes. The resulting mixture was hot melt coated between two releaseliners at 150° C. using a HAAKE single screw extruder (commerciallyavailable from Haake, Inc.; Paramus, N.J.) equipped with a draw die togive a thickness of 51 or 127 micrometers. The probe tack properties ofthe film were determined as described in the Probe Tack Test methodabove. The results are shown in Table 15. TABLE 15 Level of Probe Tackfor 127 Probe Tack for 51 ATTANE 4202 micrometer thick micrometer thickExample (weight %) sample (grams) sample (grams) C19 0 442 376 31 10 340328 32 20 384 316

Examples 33-37 and Comparative Example C20

The mixtures for Examples 33-37 and Comparative Example C20 wereprepared using PSA-4 with the level of ATTANE 4202 shown in Table 16mixed in a BRABENDER mixer (commercially available from C.W. BrabenderInstruments, South Hackensack, N.J.) at 140° C. to 150° C. for 8 to 10minutes. The resulting mixture was hot melt coated between two releaseliners at 150° C. using a HAAKE single screw extruder (commerciallyavailable from Haake, Inc.; Paramus, N.J.) equipped with a draw die togive a thickness of 51 or 127 micrometers. The probe tack properties ofthe film were determined as described in the Probe Tack Test methodabove. The results are shown in Table 16. TABLE 16 Probe Level of ProbeTack for Tack for 51 ATTANE 127 micrometer micrometer 4202 thick samplethick Example (weight %) (grams) sample (grams) C20 0 249 160 33 5 261197 34 10 276 119 35 15 157 156 36 20 113 103 37 30 87 73

Comparative Examples C21-C22

A mixture of PSA-8, with ELVAX 240 were prepared with the levels ofELVAX 240 shown in Table 17 and hot melt coated as described in U.S.Pat. No. 6,063,838 (Patnode, et al) Examples 1-17. The tensileproperties of the film were determined as described in the TensileTesting method above. The results are shown in Table 17. TABLE 17 Levelof Tensile Percent ELVAX 240 Yield Strength Strength Elongation atExample (weight %) (MegaPascals) (MegaPascals) Break (%) C21 10 1.011.10 408 C22 15 1.43 1.52 460

Comparative Examples C23-C24

A mixture of PSA-8, with ELVAX 210 were prepared with the levels ofELVAX 210 shown in Table 18 and hot melt coated as described in U.S.Pat. No. 6,063,838 (Patnode, et al) Examples 1-17. The tensileproperties of the film were determined as described in the TensileTesting method above. The results are shown in Table 18. TABLE 18 Levelof Tensile Percent ELVAX 210 Yield Strength Strength Elongation atExample (weight %) (MegaPascals) (MegaPascals) Break (%) C23 10 1.381.42 470 C24 15 1.45 1.52 460

Comparative Examples C25-C26

A mixture of PSA-9, with ELVAX 240 were prepared with the levels ofELVAX 240 shown in Table 19 and hot melt coated as described in U.S.Pat. No. 6,063,838 (Patnode, et al) Examples 43-44. The tensileproperties of the film were determined as described in the TensileTesting method above. The results are shown in Table 19. TABLE 19 Levelof Tensile Percent ELVAX 240 Yield Strength Strength Elongation atExample (weight %) (MegaPascals) (MegaPascals) Break (%) C25 10 0.330.37 270 C26 15 0.32 0.36 120

Comparative Examples C27-C28

A mixture of PSA-9, with ELVAX 210 were prepared with the levels ofELVAX 210 shown in Table 20 and hot melt coated as described in U.S.Pat. No. 6,063,838 (Patnode, et al) Examples 43-44. The tensileproperties of the film were determined as described in the TensileTesting method above. The results are shown in Table 20. TABLE 20 Levelof Percent Exam- ELVAX 210 Yield Strength Tensile Strength Elongation atple (weight %) (MegaPascals) (MegaPascals) Break (%) C27 10 0.07 0.08160 C28 15 0.14 0.16 220

Comparative Examples C29-C30

A mixture of PSA-8, with ELVAX 450 were prepared with the levels ofELVAX 450 shown in Table 21 and hot melt coated as described in U.S.Pat. No. 6,063,838 (Patnode, et al) Examples 1-17. The tensileproperties of the film were determined as described in the TensileTesting method above. The results are shown in Table 21. TABLE 21 Levelof Tensile Percent ELVAX 450 Yield Strength Strength Elongation atExample (weight %) (MegaPascals) (MegaPascals) Break (%) C29 10 1.651.72 260 C30 15 2.55 2.69 270

Comparative Examples C31-C32

A mixture of PSA-8, with ELVAX 660 were prepared with the levels ofELVAX 660 shown in Table 22 and hot melt coated as described in U.S.Pat. No. 6,063,838 (Patnode, et al) Examples 1-17. The tensileproperties of the film were determined as described in the TensileTesting method above. The results are shown in Table 22. TABLE 22 Levelof Tensile Percent ELVAX 660 Yield Strength Strength Elongation atExample (weight %) (MegaPascals) (MegaPascals) Break (%) C31 10 2.412.48 220 C32 15 2.14 2.21 240

Examples 38-41

The mixtures for Examples 38-41 were prepared using PSA-5 with the levelof ATTANE 4202 shown in Table 23, were mixed in a BRABENDER mixer(commercially available from C.W. Brabender Instruments, SouthHackensack, N.J.) at 140° C. to 150° C. for 8 to 10 minutes. Theresulting mixture was hot melt coated between two release liners at 150°C. using a HAAKE single screw extruder (commercially available fromHaake, Inc.; Paramus, N.J.) equipped with a draw die. The solventextraction properties of the film were determined as described in theSolvent Extraction Test method above. The results are shown in Table 23.TABLE 23 Level of ATTANE 4202 Solvent Extraction Example (weight %) TestResult 38 10 Pass 39 15 Pass 40 30 Pass 41 40 Pass

Example 42

The film of Example 10 was formed as described in the Example exceptthat the screw speed of the extruder was 100 rpm and the draw ratio was4. The PSA material was washed away with ethyl acetate and the diameterof the dispersed phase fibers was measured using scanning electronmicroscopy (SEM). The fibers were fine with diameters of 0.2 to 0.3micrometers. The diameter of the fibers can be controlled by varying thedraw ratio to obtain values from 60 nanometers to 3 micrometers.

Example 43

The film of Example 20 was formed as described in the Example exceptthat the thickness was about 127 micrometers, the screw speed of theextruder was 100 rpm, and the draw ratio was 4. The elongated structuresof the dispersed phase material had a diameter of roughly 0.5micrometers. The film was applied on a glass slide with the fibersaligned in the vertical direction. Collimated light from a broadbandwhite light source was directed at the film. The light diffused from thefilm was visualized on a diffuse glass window. The diffuse light spot onthe glass window was captured with a handheld digital camera. The imagewas analyzed and it was determined that the horizontal dispersion oflight was substantially larger (at least ten times) than the verticaldispersion.

A piece of this film was applied on a glass slide and placed into aheating stage. A collimated light beam from a broad band white lightsource was incident on the film. A diffused light spot was monitoredusing a digital camera. The heating stage temperature was changed fromroom temperature to 150° C. The heating stage was heated from 25° C. to100° C. with a 10° C. per minute rate; a 2 minute pause at 100° C.; andthen heated to 150° C. at a rate of 2° C. per minute with a 2 minutepause after each 10° C. increase. It was observed that as the heatincreased, the diffused light spot became less symmetric. It is believedthat the heat causes the fibers to break and become spherical particles.

Example 44

Four films were formed using PSA-4 as the adhesive material and ATTANE4202 as the dispersed phase material. Film A had 40 wt. % dispersedphase material and a thickness of about 125 micrometers. The screw speedof the extruder was 100 rpm and the draw ratio was 4. Film B had 20 wt.% dispersed phase material and a thickness of about 125 micrometers. Thescrew speed of the extruder was 100 rpm and the draw ratio was 4. Film Chad 20 wt. % dispersed phase material and a thickness of about 250micrometers. The screw speed of the extruder was 100 rpm and the drawratio was 2. Film D did not include any dispersed phase material. Thescrew speed of the extruder was 100 rpm and the draw ratio was 4.

The blends for each of these films were. prepared by mixing the adhesivematerial and the dispersed phase material in a BRABENDER mixer (C.W.Brabender Instruments, South Hackensack, N.J.) at 150° C. to 160° C. for10 to 15 minutes. The resulting mixture was hot melt coated between 2release liners (50 micrometer silicon polyester liner from 3M Company,St. Paul, Minn. and a paper line) at 150° C., a screw speed of 100 rpm,and a draw ratio of 2 using a HAAKE single screw extruder (commerciallyavailable from Haake, Inc.; Paramus, N.J.) equipped with a draw die.

Each of the films was disposed on a portion of a luminescent film toextract light from the luminescent film. The luminescent film containeda fluorescence dye that emitted green fluorescence upon absorbing bluelight. Because the luminescent film trapped light due to internalreflection, the edges of the film emitted bright light. The luminescentfilm was illuminated using a tungsten light source (Model 576, StahlResearch Laboratories). A bandpass filter centered on 450 nm with 20 nmbandwidth was used to filter all but the blue light (around 450 nm) fromincidence on the luminescent film. A microscope (Leitz TransmissionMicroscope) was used to collect the green fluorescence using anobjective of 4×/0.06 (NA). A spectrometer (Leitz MPV-Sp) was placed ontop of the microscope to record the fluorescence light. The amount ofextracted light was determined for each film, as well as for theluminescent film alone (designated “No Film”). The results are displayedin FIG. 6. The lines from top to bottom correspond to Film C, Film B,Film A, No Film, and Film D.

Example 45

A film was formed using PSA-4 as the adhesive material and ATTANE 4202as the dispersed phase material. The film had 20 wt. % dispersed phasematerial and a thickness of about 250 micrometers. The film was preparedby mixing the adhesive material and the dispersed phase material in aBRABENDER mixer (C.W. Brabender Instruments, South Hackensack, N.J.) at150° C. to 160° C. for 10 to 15 minutes. The resulting mixture was hotmelt coated between 2 release liners (50 micrometer silicon polyesterliner from 3M Company, St. Paul, Minn. and a paper line) at 150° C., ascrew speed of 100 rpm, and a draw ratio of 2 using a HAAKE single screwextruder (commercially available from Haake, Inc.; Paramus, N.J.)equipped with a draw die.

A polarizer (Model No. 03FPG003, Melles Griot, Irvine, Calif.) is placedafter a fiber optical light source (Fostec DDL with a fiber bundle,Auburn, N.Y.). The linearly polarized light is then incident on thefilm. The fiber light source, the polarizer and the film holder wereplaced on a rotating stage. The diffused light from the film passesthrough an analyzer (Model No. 03FPG003, Melles Griot, Irvine, Calif.)placed before a photodetector (Minolta Luminance Meter LS-100), whichwas placed at a distance so that only a small cone of light (<2⁰) wasdetected by the detector. The extinction ratio at each angle wasmeasured as the ratio of light intensity with the analyzer and thepolarizer were in parallel and perpendicular positions. Differentdiffusing angles were observed by rotating the rotation stage withrespect to the detector and the analyzer. The results of thesemeasurements are plotted in FIG. 7. At a diffusion angle of 50°, theextinction ratio is still more than 100. This indicates that thedepolarization of the scattered light is relatively small for each highscattering angles.

Example 46

A film was formed using PSA-4 as the adhesive material and ATTANE 4202as the dispersed phase material. The film had 20 wt. % dispersed phasematerial and a thickness of about 250 micrometers. The film was preparedby mixing the adhesive material and the dispersed phase material in aBRABENDER mixer (C.W. Brabender Instruments, South Hackensack, N.J.) at150° C. to 160° C. for 10 to 15 minutes. The resulting mixture was hotmelt coated between 2 release liners (50 micrometer silicon polyesterliner from 3M Company, St. Paul, Minn. and a paper line) at 150° C., ascrew speed of 100 rpm, and a draw ratio of 2 using a HAAKE single screwextruder (commercially available from Haake, Inc.; Paramus, N.J.)equipped with a draw die.

Gain curves were determined as described in U.S. Pat. No. 6,163,402,incorporated herein by reference. The gain curves in the horizontal(perpendicular to the orientation of the elongated structures ofdispersed phase material) and vertical (parallel to the orientation ofthe elongated structures of dispersed phase material) directions weremeasured. Gain is a measure of brightness as a function of viewing anglefor collimated incident light normalized relative to a lambertiandiffuser. The results for the horizontal and vertical directions areprovided in FIG. 8. The film had a peak gain of 24.2, a horizontalviewing angle (measured as half of the peak gain) of 12 degrees and avertical viewing angle of 3 degrees. The average transmission of thisfilm from 400 to 700 nm was 86.5%.

Example 47

A film was formed using PSA-4 as the adhesive material and ATTANE 4202as the dispersed phase material. The film had 20 wt. % dispersed phasematerial and a thickness of about 500 micrometers. The film was preparedby mixing the adhesive material and the dispersed phase material in aBRABENDER mixer (C.W. Brabender Instruments, South Hackensack, N.J.) at150° C. to 160° C. for 10 to 15 minutes. The resulting mixture was hotmelt coated between 2 release liners (50 micrometer silicon polyesterliner from 3M Company, St. Paul, Minn. and a paper line) at 150° C., ascrew speed of 100 rpm, and a draw ratio of 1 using a HAAKE single screwextruder (commercially available from Haake, Inc.; Paramus, N.J.)equipped with a draw die.

Gain curves were determined as described in U.S. Pat. No. 6,163,402,incorporated herein by reference. The gain curves in the horizontal(perpendicular to the orientation of the elongated structures ofdispersed phase material) and vertical (parallel to the orientation ofthe elongated structures of dispersed phase material) directions weremeasured. Gain is a measure of brightness as a function of viewing anglefor collimated incident light normalized relative to a lambertiandiffuser. The results for the horizontal and vertical directions areprovided in FIG. 9. The film had a peak gain of 7.9, a horizontalviewing angle (measured as half of the peak gain) of 26 degrees and avertical viewing angle of 5 degrees. The average transmission of thisfilm from 400 to 700 nm was 73.3%.

Example 48

A film was formed using PSA-4 as the adhesive material and ATTANE 4202as the dispersed phase material. The film had 20 wt. % dispersed phasematerial and a thickness of about 500 micrometers. The film was preparedby mixing the adhesive material and the dispersed phase material in aBRABENDER mixer (C.W. Brabender Instruments, South Hackensack, N.J.) at150° C. to 160° C. for 10 to 15 minutes. The resulting mixture was hotmelt coated between 2 release liners (50 micrometer silicon polyesterliner from 3M Company, St. Paul, Minn. and a paper line) at 150° C., ascrew speed of 100 rpm, and a draw ratio of 1 using a HAAKE single screwextruder (commercially available from Haake, Inc.; Paramus, N.J.)equipped with a draw die. The film was laminated to a visible mirror.The mirror was a multilayer optical film, such as those described inU.S. Pat. No. 5,882,774, incorporated herein by reference. The mirrorhad an average reflectivity of more than 99% in the visible light range.

Gain curves were determined as described in U.S. Pat. No. 6,163,402,incorporated herein by reference. The gain curves in the horizontal(perpendicular to the orientation of the elongated structures ofdispersed phase material) and vertical (parallel to the orientation ofthe elongated structures of dispersed phase material) directions weremeasured. Gain is a measure of brightness as a function of viewing anglefor collimated incident light normalized relative to a lambertiandiffuser. The results for the horizontal and vertical directions areprovided in FIG. 10. The average reflectance of this film from 400 to700 nm was 88.2%.

The present invention should not be considered limited to the particularexamples described above, but rather should be understood to cover allaspects of the invention as fairly set out in the attached claims.Various modifications, equivalent processes, as well as numerousstructures to which the present invention may be applicable will bereadily apparent to those of skill in the art to which the presentinvention is directed upon review of the instant specification.

1. A screen for managing light comprising: a substrate; and a polymeric composition disposed on the substrate, the polymeric composition comprising adhesive material; and dispersed phase material disposed as a plurality of elongated structures within the adhesive material, each elongated structure having a major axis, wherein the major axes of the elongated structures are substantially aligned and the dispersed phase material has an index of refraction that differs by at least 0.01 from an index of refraction of the adhesive material.
 2. An optical element comprising: a substrate; and a polymeric composition disposed on the substrate, the polymeric composition comprising adhesive material; and dispersed phase material disposed as a plurality of elongated structures within the adhesive material, each elongated structure having a major axis, wherein the major axes of the elongated structures are substantially aligned and the dispersed phase material has an index of refraction that differs by at least 0.01 from an index of refraction of the adhesive material.
 3. An optical element according to claim 2 wherein the optical element manages light to provide a first viewing angle in a first direction and a second viewing angle in a second direction, the first direction being substantially perpendicular to the second direction, and wherein the first viewing angle is broader than the second viewing angle.
 4. An optical element according to claim 2 further comprising a lenticular structure.
 5. An optical element according to claim 2 further comprising a polarizer.
 6. An optical element according to claim 2 further including a fresnel lens.
 7. An optical element according to claim 2 further including a reflective element.
 8. A screen according to claim 2 wherein the polymeric composition is a pressure sensitive adhesive composition.
 9. A method of making an optical element with preferential light scattering directions, the method comprising: forming a polymeric composition comprising a first adhesive material and a second polymeric material dispersed within the first adhesive material, wherein an index of refraction of the first adhesive material differs by at least 0.01 from an index of refraction of the second polymeric material; and dispensing the polymeric composition on a substrate, wherein the dispensing results in the second polymeric material forming a plurality of elongated structures within the first adhesive material, each elongated structure having a major axis with the major axes of the elongated structures being substantially aligned.
 10. A method of making an optical element according to claim 9 wherein the polymeric composition is a pressure sensitive adhesive composition.
 11. A method of making an optical element with preferential light scattering directions, the method comprising: forming a polymeric composition comprising a first polymeric material and a second polymeric material dispersed within the first polymeric material, wherein an index of refraction of the first polymeric material differs by at least 0.01 from an index of refraction of the second polymeric material; and dispensing the polymeric composition on a substrate, wherein the dispensing results in the second polymeric material forming a plurality of elongated structures within the first polymeric material, each elongated structure having a major axis with the major axes of the elongated structures being substantially aligned, wherein dispensing the polymeric composition comprises dispensing the polymeric composition on a substrate at a temperature wherein a shear viscosity of the second polymeric material is within the range of 0.5 to 2 times a shear viscosity of the first polymeric material.
 12. A method of making an optical element according to claim 11 wherein the polymeric composition is a pressure sensitive adhesive composition.
 13. An optical system comprising: an illumination source for providing light, an optical element having an incident surface for receiving light from the illumination source and a viewing surface, the optical element comprising: an adhesive material and a dispersed phase material disposed as a plurality of elongated structures within the adhesive material, each elongated structure having a major axis, wherein the major axes of the elongated structures are substantially aligned and the dispersed phase material has an index of refraction that differs by at least 0.01 from an index of refraction of the adhesive material, and wherein the elongated structures are sized, shaped and positioned to asymmetrically diffuse light from the illumination source.
 14. An optical system according to claim 13 wherein the optical element manages light to provide a first viewing angle in a first direction and a second viewing angle in a second direction, the first direction being substantially perpendicular to the second direction, and wherein the first viewing angle is broader than the second viewing angle.
 15. An optical system according to claim 13 further comprising a lenticular structure.
 16. An optical system according to claim 13 further comprising a polarizer.
 17. An optical system according to claim 13 further comprising a fresnel lens.
 18. An optical system according to claim 13 further including a reflective element.
 19. An optical system according to claim 13 wherein the illumination source provides polarized light.
 20. An optical system according to claim 13 wherein the adhesive material is a pressure sensitive adhesive material. 